Enameled cast iron is made by coating raw cast iron with a glass dust, then firing the piece at approximately 1400F. At this temperature the glass powder melts and fuses into a smooth surface covering the cast iron. By including different metal oxides with the glass dust it is possible to incorporate colors with the enamel finish. The extra time and material required for enameling means a good enameled cast iron grill pan will always cost more than its seasoned equivalent.
The cooking surface in an enameled grill pan is essentially a very tough form of glass giving the pan exceptional resistance to chemical attack. That is, they don’t rust! Although the surface is very tough it is still glass and is subject to cracking and chipping if roughly handled or scraped with metal utensils.
An important detail about enameled grill pans is that they are not inherently non-stick. This is a point of major frustration for many people who shell out the extra money for an enameled grill pan over a seasoned one. Manufacturers of enameled grill pans instruct users to make sure their food is lightly oiled before adding to the pan as this will help with food release.
The trick to using an enameled grill pan is to let it get dirty. Le Creuset instructs that over time a Patina, an oily brown or black residue, will form on the grill surface which will enable truly fat free cooking. Really all we are saying is that like cast iron, enameled cast iron will need to season to become truly non-stick. So, use your grill pan often with lightly oiled food and gently clean it after each use. Clean it enough to remove bits and flecks of food but not so much that it looks brand new. One manufacturer summarizes the process very well by instructing users to “respect the Patina”.
Other manufacturers of enameled cast iron grill pans will go ahead and coat the enamel with a non-stick polymer. I believe GreenPans, makers of the Martha Stewart and Todd English grill pans, uses a coating of Thermolon. Another manufacturer, Staub, has the interior enamel be black so people don’t get concerned about discoloration.
The major benefits of enameled cast iron over seasoned cast iron are appearance and care. Some people just love the look of enameled cast iron and I can see their point. Personally I think Les Creuest cookware is beautiful. Additionally, if you don’t get enameled cast iron completely dry it is not going to rust on you like seasoned cast iron will.